In general, materials are very important factors to determine the property and the performance of final products in the electric, electronic and mechanical industrial fields.
Since silicon (Si) used as a representative semiconductor device material is weak at the temperature of 100° C. or above, a semiconductor device may erroneously operate or may be failed frequently, so the semiconductor device requires various cooling apparatuses. As silicon (Si) has the physical limitation, wideband semiconductor materials such as SiC, GaN, AlN, and ZnO have been spotlighted as next semiconductor device materials.
In this case, when comparing with GaN, AlN, and ZnO, SiC represents the superior thermal stability and superior oxidation-resistance property. In addition, the SiC has the superior thermal conductivity of about 4.6 W/Cm° C., so the SiC can be used for fabricating a large-size substrate having a diameter of about 2 inches or above. In particular, a silicon carbide epi wafer having a high quality, which is heavily doped at a low concentration, can be used in the field of high-power devices.
According to the related art, in order to grow the silicon carbide epi layer on a wafer, the silicon carbide is deposited on the wafer in a chamber and an annealing process and/or a cooling process is performed to provide an epi wafer on which the silicon carbide epi layer has been grown.
That is, according to the related art, a silicon carbide wafer has been introduced into a single or batch-type reaction chamber and a layer has been deposited on the silicon carbide wafer. Then, in general, the wafer has been introduced into an annealing apparatus and/or a cooling apparatus and processes for removing defects on the surface of the wafer have been performed in sequence, such that a silicon carbide epi wafer has been manufactured.
At this time, if the epi wafer manufactured through the cooling step after growing an epi layer is exposed to the outside of the chamber, a surface of an epi thin film may be contaminated with external impurities. Thus, the product yield of the epi wafer may be lowered.
Therefore, there is necessary to provide a method of fabricating the silicon carbide epi wafer which can protect the surface of the epi wafer from the contamination caused by external impurities after growing a silicon carbide epi layer.